The salt is commonly associated with gypsum, often also with anhydrite, and occasionally with sylvite, carnallite and other minerals containing potassium and magnesium.
News, 1864, 10, p. 181), and, associated with rubidium, at Diirkheim; it is also found in lepidolite, leucite, petalite, triphylline and in the carnallite from Stassfurt.
There is also deposited a double magnesium and potassium chloride, similar to the carnallite of Stassfurt, and finally the mother-liquor, which has now again risen to specific gravity 1.3374, contains only pure magnesium chloride.
For the purpose of the manufacturer of this salt these are assorted into a raw material containing approximately, in Ioo parts, 55-65 of carnallite (representing 16 parts of potassium chloride), 20-25 of common salt, 15-20 of kieserite; 2-4 of tachhydrite (CaC12 2MgC12 12H20), and minor components.
Smaller pieces are thrown into a bath of melted carnallite and pressed together with an iron rod, the bath being then heated until the globules of metal float to the top, when they may be removed in perforated iron ladles, through the holes in which the fused chloride can drain away, but through which the melted magnesium cannot pass by reason of its high surface tension.
Hydrogen is found in the free state in some volcanic gases, in fumaroles, in the carnallite of the Stassfurt potash mines (H.
In later processes, carnallite (a natural double chloride of magnesium and potassium) has commonly, after careful dehydration, been substituted for the single chloride.
The carnallite principally dissolves and crystallizes out relatively pure on cooling.
The Stassfurt deposits are of special importance for the sake of the associated salts of potassium and magnesium, such as carnallite and kainite.
Very thin laminae of haematite, blood-red by transmitted light, occur as microscopic enclosures in certain minerals, such as carnallite and sun-stone, to which they impart colour and lustre.